Electron discharge device



May 5,` P931. F. w. HocHsTETTER m@ ELECTRON DISCHARGE DEVICE Filed March 27, 195o zal@ Patented May 5, 1931 `minimalen w. nocnsrn'r'rnn; or rrr'rsBUReH, PENNSYLVANIA ELEcraoN' DISCHARGE nnvrcn Application led March 27, 1930.. Serial No. 439,280.

My invention relatesin general to that type of electron discharge device including {ilament, grid and plate electrodes.- In particular it relates to a device of this type in which 5 two grids are included instead of the usual single grid, the grids being so positioned and so connected into the circuit that the;1 are always at opposite phase and so that the electron attracting or repelling effect of `one is` 10 complementary to that of the other with respect to the plate. By my invention I am able to secure increased plate voltage without increasin the plate impedance or introduciniinsta ility in the circuit.

'c ne form of my invention is illustrated by the drawing, of which- Figure l is a side elevation. of a tube with the outer envelope partly broken away to show the arrangement of the electrodes, and

the manner in which the tube of Fig. .1. may be used.

Referringto Fig. l the device consists of l an evacuated enclosing envelope 1, preferably of glass, equipped. with the usual base 2 through which the Ileads from the electrodes run to the usual prongs 3. Positioned within the envelope is a plaie 4, preferably cylindrical in form, within which is the usual grid 30 5 and fiiament 6. A second grid 7 is mounted within thefilament 6.. For convenience in manufacture and to insure proper spacing Vbetween the filament 6 and the grid 7 1 prefer to provide the usual insulating and supporting stem 8 with a hollow cylindrical extension 9 of glass or other dielectric. The lament may conveniently be wound .upon this extension,. as shown, and the second grid 7 insorted within it after which the atmosphere within extension 9 may be exhausted; Also the other grid 5 and the plate 4 .may be supf ported in part bythe projection 9, thus secur ing ri 'dity and permanence in the positioning o the electrodes. The usual leads are carried in the usuai way through .stem 3 to the' contact rangs 3, of whichtherc are .tive (instead of t. e usual four onaccount cf the extra grid. The tube which I have described is ,prefT 5G" .erably employed in l. circuit having the gen- Fig. 2 is a diagram. of a circuit to illustrate eral character of that illustrated' by Fig. '2; In Fig. 2 the signal energy is impressed upon the tube through a transformer 10, one end of the secondary of which is connected to the grid 5 and. the other end to the grid 7 i' Any ESAS` desired amount of bias may be imposed upon the grids by means of a C battery ll-in cirs cuit between one 'side' of the filamentand a tap 12 in the secondary winding of transformer 10. The filament circuit is convenf @0 tional, including the usual .A battery 13, as is the plate circuit` with its B battery 14..

As a result of this arrangement tbe two grids will .always be in oppor te'phase and einer: one grid is outside of the filament and @5' one inside their action upm the v* assago-of electrons from the filament Lo the nlate will be either assisting or retarding. That is to say when grid 5 is positive it Wil-laid the flow of electrons from the flament to 'the i, plate. At the same time grid will be negu` atiife and repellant to electrons, but because it is located upon the other side ofthe iilament it will tend to drive the electrons to-4 ward the plate and, therefore, aid grid 5 in 75 this respect. Similarly, when grid' is neg-- ative and consequently repellant to electrons, gird will be positive and attactive to electrous, with the result that one grid aids the other in deceasing the ow of electrons to the 59 rid. g In this way the electronic action of the tube is magnified. In this way the two grids work together to control the operation of the tube more effectively and more eiciently'than is 85 possible with the ordinary, single grid arrangement. 4 In 'the above description'l have referred to thegrids as being positive or ne ative for the sake of simplicity. It will, o course, be understood that these terms are used in an illustrative sense only and would more ac curately be stated as fmorepositive or. more negative since it 1:; not necessar for them to actually change their polarity to obtain @5 the desired ecc Thus, without increasing the inter-electrode capacities or the internal impedance of the tube the amplification factor may be materially increased; `Furthermore,` by the use m0 of an input transformer having a center tap secondary winding, as shown 1n Fig. 2, the

tendency towards feed-back through the common impedance of thelA, B and C battery s circuits is reduced. The reference to the A,

B and C batteries is, of course, purely conventional since my device will operate with equal success with any suitable form of power 'packor other device whereby'batteries are '10 eliminated.

I claim:

1. An electron discharge device comprising an evacuatedenvelope,aplateiand filament therein, a grid between said plate and filament, a dielectric stem withinvsaid filament and a second grid within said stein.`

2. An electron discharge device comprising an evacuated envelope, containing a'cylindrical plate, a grid within said plate concentric therewith, a filament within said grid and concentric therewith, and a second grid within said filament, said filament and said second grid being separated by a dielectric stem. g5 3. An electron discharge device comprising an evacuated envelope, containing a cylindrical plate, a grid within said plate concentric therewith, a ilament within said grid -and concentric therewith, and a second gridv so within said lament, said filament being wound upon a hollow dielectric stem, and said second grid being positioned within said stem. 4. 'An electron discharge device including an anode, a cathode and two grid electrodes,

one of said grid electrodes being separated from the other electrodes by a dielectric in the form of an exhausted container.

- 5. An electron discharge device comprising an evacuated envelope, a plate and lament 40 therein, a gridbetween said plate and lilament, anexhausted dielectric stem within zd filament, and a second grid within said m. ln testimony whereof I have hereunto set Ipgsiand on this 4th day of March, A.- D.

FREDERICK w. HOCHSTETTER. 

